小鼠十二指肠运动中NO对NA作用的影响及机制  

Effect and its mechanism of NO on NA action on contractile activityof duodenum muscle strips of mouse

作　　者：王晓敏[1] 胡还忠[1] 余承高[1] 马立群[1] 汪长东[1] 田琴[1] 

机构地区：[1]华中科技大学同济医学院生理系,武汉430030

出　　处：《胃肠病学和肝病学杂志》2005年第2期117-120,124,共5页Chinese Journal of Gastroenterology and Hepatology

摘　　要：目的观察去甲肾上腺素(noradrenaline ,NA)对离体小鼠十二指肠肌条收缩幅度及一氧化氮(nitricoxide ,NO)对NA作用的影响;探讨NO和NA之间的关系及影响机制。方法用器官浴槽孵育离体小鼠十二指肠肌条,以肌张力收缩幅度抑制比为指标观察NA对肌条收缩幅度及NO对NA作用的影响。结果NA对肌条的收缩幅度有明显的抑制作用,在浓度1.2×10 -4～1.2×10 -8mol/L范围内,呈剂量-效应关系,其中1.2×10 -8mol/L组与对照组之间无显著性差异(P >0 .0 5 )。L Arg对肌条的收缩幅度有明显的抑制作用,在浓度2×10 -2 ～2×10 -6mol/L范围内,呈剂量-效应关系。除2×10 -6mol/L组外,其余各浓度的L Arg与对照组均有显著性差异(P <0 .0 0 1)。用无反应剂量2×10 -6和2×10 -3 mol/L的L Arg孵育标本后加入NA ,浓度为1.2×10 -5,1.2×10 -6,1.2×10 -7,1.2×10 -8mol/L的NA对肌条收缩幅度的抑制作用明显增强,与单独NA组的作用相比差异有显著性(P <0 .0 0 1) ;而1.2×10 -4mol/LNA组与单独NA组的作用相比差异无显著性(P >0 .0 5 )。分别用一氧化氮合酶(NOS)的抑制剂L NNA、可溶性鸟苷酸环化酶(sGC)抑制剂ODQ、α肾上腺素能受体阻断剂酚妥拉明(phentolamine)均使NA对肌条收缩幅度抑制效应明显减弱,与对照组比较有显著性差异(P <0 .0Aim To observe the effects of NA (noradrenaline) on the contractile amplitude of isolated duodenum muscle strips and the influences of NO (nitric oxide) on the NA action in mouse, and to explore its underlying mechanism.Methods Isolated strips were incubated in an organ bath. The effects of NA on contractile amplitude and the influences of NO on NA action were observed.Results Noradrenaline(NA) significantly decreased the contractile amplitude of muscle strips in a dose-dependent manner from 1.2×10^-4 to 1.2×10^-8 mol/L. Compared with control groups, NA(1.2×10^-8 mol/L) showed no effect on the contractile amplitude, while NA (1.2×10^-4 mol/L) completely inhibited contractile amplitude. L-Arg decreased the contractile amplitude of the strips in a dose-dependent manner from 2×10^-2 ～2×10^-6 mol/L. Compared with control groups, L-Arg (2×10^-6 mol/L)showed no effect on the contractile amplitude(P>0.05 ), while L-Arg (2×10^-5 , 2×10^-4 , 2×10^-3 , 2×10^-2 mol/L) showed significant inhibitory effects on the contractile amplitude(P<0.001). So 2×10^-6 mol/L and 2×10^-3 mol/L were chosen as experimental dose. 1.2×10^-8 and 1.2×10^-6 mol/L NA increased the effects of L-Arg (2×10^-6 ～2×10^-3 mol/L) on the muscle strips contraction(P<0.001). This effects of NA could be inhibited by L-NNA(general inhibitor of NOS), ODQ (inhibitor of sGC), phentolamine (blocker of a adrenergic receptor)(P<0.001). Conclusions NA could decrease the contractile amplitude of duodenum in mouse. NO can strengthen NA inhibitory action by promoting the release of NO.

关 键 词：去甲肾上腺素 一氧化氮 ODQ 左旋-硝基精氨酸 酚妥拉明 十二指肠 收缩 幅度 

分 类 号：R333[医药卫生—人体生理学] Q48[医药卫生—基础医学]